CN110599261A

CN110599261A - Electric automobile safety electric power transaction and excitation system based on energy source block chain

Info

Publication number: CN110599261A
Application number: CN201910895626.6A
Authority: CN
Inventors: 张小红; 陈晓峰
Original assignee: Jiangxi University of Science and Technology
Current assignee: Jiangxi University of Science and Technology
Priority date: 2019-09-21
Filing date: 2019-09-21
Publication date: 2019-12-20
Anticipated expiration: 2039-09-21
Also published as: CN110599261B

Abstract

An electric vehicle safe electric power transaction and excitation system based on an energy source block chain comprises three main entities, namely an electric vehicle, a charging infrastructure and a vehicle service center. When the electric vehicle and the charging infrastructure or other electric vehicles carry out electric power transaction, the digital signature technology based on the bilinear pairing property on the elliptic curve is adopted to ensure the authenticity and reliability of the vehicle identity and the sent information. And in the data block consensus stage, a practical Byzantine fault-tolerant consensus algorithm is adopted so as to improve the fault-tolerant capability and the throughput of the whole network. Each charging infrastructure node stores the distributed account book of the energy source block chain in the built-in data processor. In addition, in order to incentivize the legally compliant participation of the electric vehicle in the electric power transaction, a smart contract for triggering a condition and an incentive mechanism for an energy coin award expressed according to the energy contribution amount are set. The enthusiasm of vehicle electric power transaction is promoted by an incentive contract based on game theory, so that the system is more active and stable.

Description

Electric automobile safety electric power transaction and excitation system based on energy source block chain

Technical Field

The invention belongs to the field of block chain information safety, and relates to safe transmission and storage of Electric power transaction data of an Electric Vehicle (EV) energy market.

Background

The power of the electric automobile is provided by a vehicle-mounted power supply, and the electric automobile drives the vehicle to run through a motor. As an important component of smart Grid technology, a Vehicle-to-Grid (V2G) network of electric vehicles will greatly improve and improve the operation performance of the power system. In order to meet the challenges of global energy crisis and environmental problems, electric automobiles are used as a technical solution of sustainability problems to replace traditional internal combustion engine vehicles, and compared with traditional transportation methods, the electric automobiles have the advantages of zero emission, high efficiency, low cost and the like. In the future, the electric vehicle firstly performs Charging and discharging service with a Charging Infrastructure (CI), and then the Charging Infrastructure performs information interaction and power transmission with the smart grid. Therefore, the electric vehicle will also play a new role in energy trading with the power grid.

Energy market networks include a number of components, including electric vehicles, charging infrastructure (e.g., large charging stations, personal charging posts, and battery replacement stations), Vehicle Service Centers (VSCs), and Local Aggregators (LAGs). The electric vehicle may perform power transaction and communication services with a CI or other electric vehicle. In the V2G energy exchange, data generated by electricity trading is very valuable to energy companies. The energy company analyzes and adjusts the power load of each region through the transaction data to prevent grid overload, system instability, and energy loss. A large amount of energy transaction data is stored in the central node, which can lead to serious security and privacy leakage problems if the central node is attacked. Some malicious operators will seriously threaten the security and privacy of electric vehicles through various malicious attacks. Such as leakage of license plate information, counterfeit locations, illegal charging services for advertisements, etc. In order to meet the safety challenge of information interaction and data storage between vehicles, many researchers have proposed corresponding solutions.

Rongxing Lu et al, university of ludisia, published in the conference paper of IEEE INFOCOM 2010, proposed a privacy protection scheme, called SPRING for short. According to the scheme, the trusted third party participates in the dynamic change of the user name of the vehicle to achieve the effect of protecting the privacy of the user, but the scheme is high in communication overhead and does not meet the real-time performance of vehicle shared data. Due to trust in communication and privacy issues between vehicles, Jun Shao et al, university of industry, zhejiang, published in a paper by IEEE Transactions on Vehicular Technology, proposed a new authentication protocol scheme (IBCPPA) in a decentralized group model using a new group signature. This scheme has threshold authentication, non-forgeability, traceability, etc. Maria Azees et al, university of Anna, published in an article by IEEE Transactions on Intelligent transportation Systems, proposed an effective anonymous authentication scheme (EAAP) to prevent the participation of malicious vehicles in VANETs. Although the above-mentioned schemes can solve the safety of vehicle transaction, another problem of safety and expandability of data storage is also introduced. With the rapid development of the electric automobile market, the demand of electric energy is gradually increased, and higher requirements are put on the storage of a large amount of transaction data. The electricity trading information generated by the traditional energy market is stored in a centralized authority, and a great deal of effort and high cost are required for maintenance and management. The centralized storage is generally understood as the existing cloud storage, which has the advantages of convenience and quickness, but also brings the risks of privacy disclosure, low server security, operation termination and the like. Once invaded by an attacker, the trusted centralized storage mode can cause problems of large-scale data leakage and the like, and can bring an unpredictable security threat to the whole system.

A novel Blockchain (Blockchain) technique is a decentralized, distributed database that uses cryptographic algorithms and consensus mechanisms to ensure that data is tamper-resistant, non-counterfeit, and traceable. The block chain generates data blocks according to time sequence and combines the data blocks into a specific data structure in a chain mode, and the specific data structure can be used for distributed computing and data sharing among network nodes. The blockchain can provide a script code system for cryptocurrency and intelligent contracts, and provides excellent technology for safe energy trading in the energy market. Many researchers will utilize blockchain technology in conjunction with the internet of things to address the security issues of trust of interaction and data storage between devices. Aiming at the problems of privacy protection and transaction safety during charging and discharging service of an electric vehicle, Rong Yu et al, the university of Guangdong industry, provides a novel point-to-point energy transaction model based on a union block chain in an IEEE Transactions on Industrial information thesis. Although the scheme solves the problem of expandability, the safety of the information transaction process cannot be completely guaranteed and the information transaction process is easy to be attacked. In order to protect vehicle privacy and stimulate information interaction between vehicles, Lun Li et al of Beijing university of Transportation proposes a novel privacy protection stimulation announcement network based on a block chain in an article of IEEE Transactions on Intelligent Transportation Systems. Tianyang Zhang et al, in los Angeles division, California, published a real-time system that combines priority and cryptocurrency in Applied Energy paper to incentivize Energy transactions between electric vehicles. Fan na et al of chanan university published in the paper of computer engineering and design, and proposed a traffic information transmission game model oriented to the internet of vehicles, thereby improving the transmission efficiency of traffic service information and reducing the selfish behavior of nodes. The above solutions have limited scalability and network efficiency, and are not suitable for large energy market networks and complex power trading systems.

Disclosure of Invention

The invention provides an energy source block chain-based electric vehicle safe power transaction and excitation system, which is used for ensuring that data transmission and storage are safely carried out during power transaction of vehicles and exciting the enthusiasm of information interaction between the vehicles.

The invention is realized by the following technical scheme.

The invention relates to an electric vehicle safety electric power transaction and excitation system based on an energy source block chain, which comprises participating bodies (see figure 1) of an electric vehicle, charging infrastructure (a large-scale charging station, a private charging pile, a battery replacement station), a vehicle service center, an intelligent power grid and a local aggregator, wherein bidirectional information interaction is realized among the participating bodies. The energy block chain distributed account book system mainly completes safe and credible transactions of the electric automobile and charging infrastructure or other electric automobiles, and the distributed account book also carries out information interaction with participating main bodies in a bidirectional mode. The energy source block chain is used as a safe distributed database of the electric automobile, charging infrastructures such as a private charging pile, a large-scale charging station, a battery replacement station, an intelligent power grid and a local aggregator are used as common identification nodes of data blocks, the electric automobile is used as a sensing data node, and the safe transaction of the energy block chain is realized through a digital signature technology and a tamper-proof traceable method. And the confirmation speed and the throughput of the power transaction are improved by adopting a fault-tolerant consistency algorithm. Meanwhile, a trading system with an incentive function is realized by combining a profit game and an intelligent contract of electric power trading between the electric automobile and the energy market, so that the whole system keeps active.

The invention relates to an electric automobile safe electric power transaction and excitation system based on an energy source block chain, which comprises the following steps:

(S01): respectively aligning electric vehicles EV in vehicle service center_iPrivate charging pile CP_jAnd large-scale charging station CS_kAnd a battery exchange station BES_nThese nodes register to obtain the real identity RID needed by transaction authentication_mAnd the basic information of the private key s.

(S02): charging infrastructure collects and aggregates power prices T of transactions_priceTime of transaction T_timeAnd address T of the transaction_locationInformation, denoted T_n＝{T_price,T_time,...,T_location}; carrying out digital signature and verifying the authenticity of the identity of the electric automobile and the reliability of the message by adopting an elliptic curve based bilinear pairing algorithm; if the identity of the vehicle is suspicious or illegal, the communication is terminated and the information of the illegal vehicle is recorded; and if the identity of the vehicle passes and is legal, continuing to prepare for receiving the transaction information uploaded by the vehicle.

(S03): the signed electric power transaction information SM_ijCaching the data in a recording pool of a data processor until the size of the data in the recording pool is equal to the size of a data block, broadcasting the data block to a consensus node of the whole network after waiting for random time, and using a Byzantine fault-tolerant consensus mechanism to achieve an agreement; where two-by-two communication between all nodes is required, the speed at which the nodes agree is made faster,the time delay is lower, so that the consensus efficiency is high.

(S04): the charging infrastructure acquires the right to record the data block, adds the right to the tail end of the energy block chain to increase the height of the whole chain by one, and simultaneously broadcasts the data to other nodes of the whole network to synchronously store the data of the block chain; on the other hand, the system awards a corresponding number of "energy credits" to the charging infrastructure.

(S05): combining the game theory and the intelligent contract, and setting constraint conditions in advance to form an excitation contract; automatically assigning rewards to contributions T according to a contractual agreement_nThe receipt generated after each execution will be recorded in the local storage.

Further, the step (S01) of registering (initializing) the electric vehicle and the charging infrastructure includes the steps of:

numbering all electric vehicles as EV_i＝(EV₁,EV₂,...,EV_μ) 1,2,. eta., i; private charging pile number is CP_j＝(CP₁,CP₂,...,CP_μ) μ ═ 1,2,. ·, j; the serial number of the large-scale charging station is CS_k＝(CS₁,CS₂,...,CS_μ) μ ═ 1,2,. ·, k; battery replacement station number BES_n＝(BES₁,BES₂,...,BES_μ)，μ＝1,2,...,n；

1) All nodes register with the vehicle service center, and obtain initialized system parameters and authentication information: the charging infrastructure obtains public parameters for verifying the identity of the electric vehicle.

2) If the electric vehicle node and the charging infrastructure node are granted legal identities, legal electric power transaction can be carried out in the energy market, and T is uploaded_n(ii) a The vehicle service center then analyzes the transaction data to schedule charging times for the system.

Further, the step (S02) of digitally signing and verifying the electric power transaction data uploaded by the electric vehicle includes the following steps:

1) firstly, selectAn elliptic curve E meeting the theoretical requirement of an elliptic curve cryptosystem is taken_pAfter (a, b), randomly selecting a prime number q, andwhereinIs a finite field. Two cyclic groups are respectively G₁And G₂And their order is q, wherein G₁Expressed as a cyclic addition group, G₂Is a cyclic multiplicative group.

2) The vehicle service center randomly selects two prime numbers P and s, wherein s is a private key of the vehicle service center, andwith 1 < s < q, P is the cycle group G₁One of the generators, and finds the public key P_pub。

3) According to the real identity RID_iCalculate pseudonym PID_iAnd the private key SK of the jth message_ijAnd an authentication parameter a_ijAnd b_ij. Finally generating a pair message M_ijSigned message SM_ijThe charging infrastructure verifies the message signature, which can be divided into single message verification and batch verification.

Further, the step (S05) includes the steps of:

1) generation of an incentive contract: the electric vehicle is registered in a vehicle service center or a government agency to obtain authentication parameters including EV_iPublic and private key pair (P)_pub,SK_i) And address W of account_i(ii) a All these authentication information uniquely identify the identity by binding the license plate number and the customer information.

Wherein SM_iIs defined as a message M_iThe digital signature of the hash digest of (1); by contract rules and terms, local aggregator and EV_iAn agreement is reached, and respective private keys are used for signature; packing the deployed contracts into Docker images and performing the Docker images on Docker sandboxesAnd (6) contract checking.

2) Issuing of incentive contracts: cooperative game is written in the form of G ═ P, S, U, where P ═ EV_s,EV_p) Representing sets of two game groups, S ═ S_s,S_p) Respectively correspond to EV_sAnd EV_pThe set of policies of (a) is,representing a revenue function set of the participant P under the S strategy pair, wherein each game group has a respective behavior strategy space; definition of EV_sHas a policy space of S_s＝(x₁₁,x₁₀,x₀₁,x₀₀) Wherein x is₁₁The electric energy is sold and the electric power information is uploaded; x is the number of₁₀Indicating a willingness to sell electric energy, but a reluctance to upload electric power information; x is the number of₀₁The system is used for indicating that the system is unwilling to sell electric energy but willing to upload electric power information; x is the number of₀₀Indicating that the user is neither willing to sell electric energy nor upload electric power information; EV (electric vehicle)_pHas a policy space of S_p＝(y₁₁,y₁₀,y₀₁,y₀₀) Wherein y is₁₁，y₁₀，y₀₁And y₀₀And S_sSimilarly.

All participating LAGs and EVs_iSufficient deposit should be paid from the respective wallet to the address of the contract.

3) Instigating execution of a contract: at game group EV_sAnd EV_pIn (2), different strategies are selected with different probabilities; strategies of two game groups are respectively selected to calculate a revenue function; and pass through EV_sAwarding energy credits, EV, to obtain electricity for sale at a node_pThe node purchases the amount of the energy currency paid by the electric energy and receives the quantity of the energy currency obtained by one piece of traffic information; and energy money consumed by other services, listing EV_sAnd EV_pUltimate profit of

The participator completes the electric power transaction and fund settlement and generates the number of the transactionAnd (4) sorting and packing, and reading the energy consumption value of the intelligent instrument arranged in the electric automobile according to the contract so as to verify the generated and consumed electric quantity and authorize payment of the energy currency. Further, the system updates the state of the energy source block chain, EV, after the contract execution is completed_iThe wallet data records and account balances are also updated.

The overall structure of the invention has five physical roles, an electric vehicle node, a charging infrastructure node, a vehicle service center node, a smart grid and a local aggregator. Fig. 1 is a distributed ledger in an energy block chain maintained by five main entities, specifically including the following contents:

1) electric vehicle node: the electric vehicle node is a sensing node in the energy source block chain, which is responsible for electric power transaction and is responsible for uploading and sharing data to the charging infrastructure and other electric vehicle nodes. Use of EV_iTo represent the ith vehicle node, where all of the vehicle node sets may be represented as EVs_n＝(EV₁,EV₂,...,EV_n)。

2) Charging infrastructure nodes: the charging infrastructure can be private charging piles, large-scale charging stations, battery replacement stations and the like to provide electric power energy for the electric vehicle and collect local electric power transaction information at the same time. All charging infrastructure nodes here have corresponding identity information and are stored on the vehicle service center and energy block chain. It is responsible for auditing and verifying the identity of the vehicle, the authenticity and the reliability of the data block.

3) Vehicle service center node: the node with the highest rights and reliability in the whole energy market is responsible for generating identity authentication information and system parameters of the electric automobile and the charging infrastructure node. The node can analyze according to the uploaded electric power transaction data, and reasonably distributes the electric power to other charging infrastructures or schedules charging peak-to-peak time periods of the smart grid. Generally speaking, the number of vehicle service center nodes is much smaller than the number of charging infrastructure and electric vehicle nodes.

4) The intelligent power grid: the node is responsible for power transmission with the charging infrastructure and can also act as a consensus node in the network to participate in a consistency protocol. It also has a built-in data processor to store data and record blockchain ledgers, as well as to store pre-arranged intelligent contracts.

5) The local aggregator node: the intelligent control system is used as an intelligent control system and is responsible for regulating and controlling the power of a power load, the aggregation of controllable electric quantity and the input and output of the power.

The symbols used in the present invention are shown in table 1:

TABLE 1 symbols used in the present invention

The safe power transmission and excitation contract model in the present invention is shown in fig. 2. The intelligent contract model shown in fig. 3 inputs the digital property and event of the contract participant from the outside and presets the condition of the event response. The game theory and the intelligent contract are combined to arrange the incentive contract in the data processor in advance, so that the two parties can pay the guarantee fund, and the collusion is prevented. Starting from the digital signature and verification phase of the power transaction message, an optimal revenue function is set using the incentive contract. And finally updating and storing the block chain state database by debugging on a Docker sandbox on the HyperLegendric Fabric.

The invention provides an electric vehicle safety electric power transaction and excitation contract system based on an energy source block chain. Traditional central database storage needs to pay a lot of manpower and material resources for maintenance, and a central mechanism is attacked, so that a lot of data is leaked at risk. Due to the large and complex topology of the electric vehicle market, the use of traditional centralized data storage has not been able to meet the requirements of security and storage. In a V2G network, a block chain technology and an energy trading market have common characteristics of intelligence, distributed nodes, sharing and the like, and an energy block chain formed by combining the two can provide safe and reliable guarantee for charging and discharging services of an electric automobile. In order to avoid the theft or the tampering of the electric power transaction information of the vehicle by a malicious attacker, a digital signature algorithm based on bilinear pairing property on an elliptic curve is adopted to sign and verify the message, so that the reliability and the non-repudiation of the message are improved. And packaging the transaction data passing the verification into blocks, and sending the blocks to the consensus node to audit and verify the validity of the data blocks. The charging infrastructure is selected as the consensus node, and compared with the electric automobile node, the consensus node has larger storage capacity and is easy to control and maintain. The invention utilizes a practical Byzantine fault-tolerant consensus mechanism to enable data blocks to achieve a consistency agreement. The algorithm has the advantages of high throughput, low time delay, high consensus efficiency and the like. And as long as the number f of the abnormal nodes meets the condition that f is less than or equal to (n-1)/3, the consensus result is not influenced, wherein n represents the total number of nodes in the whole network.

The invention provides an incentive contract based on game theory to increase the income of electric vehicles and promote the electric vehicles to select the best strategy to guarantee the safety of the protocol. By setting protocol rules in advance and arranging the excitation contract in the data processor, the operation command is automatically executed when the triggering condition is met. When a new data block is added to the energy block chain, the billing node will receive an energy coin award for the system. And in a certain time range, the accounting node distributes the reward to the electric automobile according to the size of the contributed electric energy or data quantity and a contract rule. On the other hand, the electric automobile can select the transaction price and the transaction strategy which are optimal for the income of both parties, so that the income of the electric automobile can be increased, and the activity of the system can be improved.

Drawings

Fig. 1 is a distributed ledger in a chain of energy-sourcing blocks.

Fig. 2 is a safe power transfer and excitation contract model.

FIG. 3 is an intelligent contract model.

Fig. 4 is a flow chart of the digital signature algorithm.

Fig. 5 is a distributed consensus process for the byzantine fault-tolerant algorithm.

Fig. 6 is an energy transfer scenario based on an excitation contract.

FIG. 7 shows a game in Game group EV_sThe benefits of different strategies are selected.

FIG. 8 shows a game in Game group EV_pThe benefits of different strategies are selected.

Detailed Description

In order to explain the present invention in more detail, the present invention will be further explained below with reference to specific examples.

Example 1. Secure trusted signatures for electric vehicles and charging infrastructure.

When the electric automobile carries out electric power transaction, a large amount of transaction data including basic information, charging and discharging time, position information of the electric automobile, some operation habits of users and the like are generated. The transaction data needs to be stored safely and efficiently, otherwise the transaction data is easily stolen or tampered by attackers, and even false information is broadcasted by other vehicles, so that the charging service efficiency of the electric vehicle and the stability of the system are seriously influenced. Accordingly, the power transaction data and the identity information may be anonymously authenticated using a digital signature technique based on the bilinear pairing property on the elliptic curve, e.g., S02. Fig. 4 is a flow chart of the digital signature algorithm. The specific steps of the digital signature will be described in detail below.

(1) And (5) initializing the system.

The vehicle service center initializes all the parameters in the system, including basic information of the electric vehicle and the charging infrastructure, and the like. And respectively sending the initialized parameters and the authentication information to the charging infrastructure and the newly-added electric automobile. Then an elliptic curve E meeting the theoretical requirement of the elliptic curve cryptosystem is selected_pAfter (a, b), randomly selecting a prime number q, and is a finite field. Two cycle groups are respectively G₁And G₂And their order is q, wherein G₁As a cyclic addition group, G₂Is a cyclic multiplicative group.

The vehicle service center randomly selects two prime numbers P and s, wherein s is used as a private key of the vehicle service center,with 1 < s < q, P is the cycle group G₁One generator, its public key is:

P_pub＝sP (1)

one-way hash function H: {0,1}^*→G₁The ith EV_iReal identity RID of_iHash to G₁And RID_i∈G₁. In addition, the vehicle service center can specify a common hash functionThe common parameter K of the system is (q, G)₁,G₂,e,P,P_pubH, H) broadcast to the entire network, then EV_iWith tamper-proof devices holding common parameters, e.g. EV_iReal identity RID of_iAnd a private key s of the vehicle service center. Assuming that the charging infrastructure is trusted, it will only be assigned common parameters and responsible for validating the EV_iThe authenticity of the identity and the authenticity of the message.

(2) A key of the signer is generated.

Charging infrastructure pair EV in generating signer's key phase_iAuthentication is performed in preparation for subsequent message signing. If the identity authentication is passed, continuing to perform information interaction of the electric power transaction; and if the identity authentication is not passed, the communication is terminated. The detailed steps are as follows:

1) each EV_iThe pseudonym identity and the corresponding private key are dynamically used for signature so as to prevent the location privacy of the user from being leaked. Vehicle EV_iAdopted jth pseudonym PID_ijComprises the following steps:

wherein r is_ijIs EV_iA randomly generated number of the tamper resistant device in, andsuppose EV_iTransmitted jth message M_ijAnd for signing M_ijIs the jth private key SK_ijComputing SK_ijComprises the following steps:

SK_ij＝sH(PID_ij||t₁) (3)

where s is the private key, PID, of the vehicle service center_ijAnd SK_ijCan be calculated in advance in an off-line state, so that the communication delay in the information interaction process is not influenced. t is t₁Is the timestamp of the currently generated pseudonym. Selecting an authentication parameter alpha_ijAnd beta_ij

α_ij＝r_ijP (4)

β_ij＝r_ijP_pub (5)

2) Random number alpha_ijCleaned up and prepared for the next generation of random numbers. Finally, EV_iGenerating a signing key (P) at a time of a jth message_pub,SK_ij) Identity pseudonym PID_ijAnd an authentication parameter alpha_ij，β_ij. These operations are EV_iFor message M_ijPreparation is done before signing.

(3) And generating a digital signature.

In the message signing phase, the charging infrastructure and the electric vehicle together generate a message signature that is authenticated between the vehicles. Electric automobile selecting randomized parameter epsilon_ijWherein:

ε_ij＝β_ij+h(M_ij||t₂)SK_ij (6)

t₂is the timestamp of the currently generated message signature. The EV is for the jth safety message M_ijSignature σ of_ij＝(α_ij,ε_ij) In which α is_ijIs content that is computed in advance and is independent of the message. EV (electric vehicle)_iFor message M_ijThe signed message is SM_ij＝(PID_ij,M_ij,σ_ij)。

In SM_ijAfter generation, signer EV_iIt is sent to the charging infrastructure and ready for the final verification phase. At the same time, the principal steps are clarifiedTransaction credentials for segments, including EVs_iCurrent pseudonym identity PID_ijAnd a private key SK_ijAnd prepare for the signature of the next message.

(4) A message verification phase.

If the electric automobile is in electric power transaction with the private charging pile, the verification of a single message needs to be considered; verification of batch messages exists if the electric vehicle is performing power services with a large charging station or a battery exchange station.

1) Single message authentication.

When the charging infrastructure receives a secure message SM_ij＝(PID_ij,M_ij,α_ij,ε_ij) The message is then authenticated by verifying whether the following conditions prevail:

if equation (7) holds, SM is represented_ijIndeed with SK_ijAnd PID_ijThen verifies that the vehicle identity is legitimate and receives the information. Otherwise the equation is not satisfied and the message is rejected and communication is terminated, indicating that the signature is invalid. Due to EV_iUsing dynamic pseudonymous identities, the charging infrastructure cannot obtain the true identity RID of any vehicle_ijThereby effectively protecting the privacy of the user.

2) And (5) batch verification.

The same electric vehicle may send n messages to the charging infrastructure node, and the charging infrastructure node may also receive n different vehicle messages, thus requiring that a batch verification be performed to authenticate the received messages simultaneously. SM for the invention₁＝(PID₁,M₁,α₁,ε₁)，SM₂＝(PID₂,M₂,α₂,ε₂)，…，SM_i＝(PID_i,M_i,α_i,ε_i) To represent all received n messages, where M₁，M₂,…,M_iMay be the same asMay be different. Verify if the following equation holds:

if equation (8) holds, then the message signatures are proven to be valid, and the verifier receives the messages, otherwise it rejects.

Example 2. And (3) distributed consensus and storage of power interaction data under a fault-tolerant consistency algorithm.

The energy block chain in the invention uses a PBFT consensus mechanism to solve the consensus problem of the data blocks, and the consensus process is to achieve an agreement when a fault occurs by repeating several rounds of voting. A Leader (Leader) is selected from all Preselected nodes (PSNs) as the master Node to perform the write ledger operation, and the other Preselected nodes are used as replica nodes to audit and verify the data block, e.g., S03. Fig. 5 is a flow chart of a distributed consensus using the byzantine fault tolerance algorithm of the present invention. Suppose the total number of preselected nodes in the network is n and the number of abnormal nodes is f. Selecting the vehicle service center as a leader to be recorded as PSN₀And respectively recording the battery replacement station, the intelligent power grid and the large-scale charging station as PSN₁，PSN₂And PSN₃Wherein PSN₃Is an exception node. The detailed consensus procedure is as follows:

(1) an initial demand phase.

And in a period of time, the electric automobile serves as a client to assemble the electric power transaction data into a data block, and the data block is uploaded to a nearby leader for auditing. The data block contains the digital signature information of the vehicle and the hash value of the power transaction record so that the data block can be audited and verified. And after the leader is selected, activating the execution privilege and service operation of the node.

(2) A preliminary preparation phase.

The leader requests to assign a sequence number N, and broadcasts a sequence number distribution message and a request message m of the client to the PSN of the whole network. Other PSNs generally have two options after receiving the broadcast message, one is the normal node (PSN)₁And PSN₂) Receiving, the other is differentConstant node PSN₃The reception is denied. The abnormal node is usually a rogue node or a failed node, and the operation of the abnormal node appears as no response to the request of other nodes.

(3) A preparation phase.

When the normal PSN₁，PSN₂Upon receipt of the prepare message, the integrity and legitimacy of the transaction will be verified and audited. The signature is then appended to the back of the audit result and broadcast to other replica nodes. If 2f different prepare messages are received, the node's preparation phase is complete. The maximum tolerable number of abnormal nodes of the system is f less than or equal to (n-1)/3, and all the abnormal nodes cannot broadcast normally.

(4) And (5) a confirmation stage.

The current slave node broadcasts confirmation messages to other slave nodes, and simultaneously audits whether message signatures received from other nodes are correct or not, and compares the message signatures with self messages. And if the slave node receives n-f confirmation messages, wherein the confirmation messages comprise own confirmation messages, the slave node feeds back the confirmation messages to the client.

(5) And (5) a recovery phase.

In the last phase, the master node and the slave node both receive the submit message and need to verify that the reply message signature is correct. If the slave node receives 2f +1 submitted messages passing the verification, the slave node indicates that most nodes in the network have agreed and feedback is given to the client. If the client receives f +1 identical reply messages, the sent request is proved to have the consensus of the whole network, otherwise, the client considers whether to resend the request to the leader.

Finally, the PBFT consensus is a consistency algorithm based on message transfer, and has good fault-tolerant capability to the system, reduces transmission delay and improves consensus efficiency. The content of the data block not only contains data of electric power transaction, but also comprises operation data generated when the mobile terminal device and the smart grid are connected into the network, and the like. When all nodes agree, each PSN keeps a copy and stores in a built-in data processor. However, the data processor stores only an index of the raw data indicating the location of the raw data for efficient user verification and query. The main raw data is stored on a cloud server or in a distributed database. On the other hand, through the feedback result of the distributed consensus process, the system can also find out the abnormal node for maintenance or removal, thereby maintaining the stability of the system.

Example 3. The power trading method is characterized in that power trading between an electric automobile and an energy market based on an incentive contract of a game theory.

When the electric automobile conducts electric power transaction, the game problem is that the transaction price or the transaction strategy which is the best for the income of both parties is selected. Each time a new data chunk is added to the chain of energy chunks, the preselected node will receive an "energy coin" award given by the system and automatically execute the award distribution command according to the built-in smart contract, e.g., (S05). FIG. 6 is an excitation contract-based energy transfer scenario of the present invention, wherein an electric vehicle that pre-sells electricity is denoted as an EV_sElectric vehicles with pre-purchased electric power denoted as EV_p. LAG serves as an intermediary between the grid and electric vehicles, and can convert the collected solar energy into electric energy or directly purchase energy from the grid and sell the energy to the electric vehicles, and also can provide electric energy transaction service between electric vehicles with abundant electric power and electric vehicles with insufficient electric power. Setting an optimal revenue function by combining the cooperative game problem, debugging on a Docker sandbox on the Hyperhedger Fabric after the nodes of the whole network achieve consensus through a PBFT consensus algorithm, and finally updating and storing the block chain state database. The detailed steps are as follows:

(1) and (4) generating an incentive contract.

1) Newly added electric vehicle EV_iRequiring registration at a vehicle service center or government agency to obtain certification information, including EVs_iPublic and private key pair (P)_pub,SK_i) And address W of account_i(ii) a All authentication information uniquely identifies itself by binding its license plate number and customer personal information. Assuming that the distribution of the electric vehicles obeys poisson distribution, the probability that the lambda vehicle nodes participate in the game is as follows:

2) and (4) the contract participants carry out negotiation to determine the rights and obligations of both the electric automobile and the LAG. Contract specifications are specified by authorized legal personnel, as well as trigger conditions to initiate contract execution. Message SM_iDefined as node EV_iSent message M_iThe digital signature of the hash digest of (1).

3) LAG and EV_iThe contract terms and rules are agreed upon and signed with their respective private keys, which is a new intelligent contract. And packaging the deployed contracts into Docker images, and performing contract inspection on Docker sandboxes.

(2) And (4) prompting contract issuing.

The verified contract is sent to each node using P2P, and the node stores the received contract temporarily in memory and prepares for consensus. After the energy blockchain network reaches the consensus, the contract set is diffused to each agent node in the network in a block mode. To prevent contractual collusion of two or more nodes for fraudulent charging services, all participating LAGs and EVs_iSufficient deposit should be paid from the respective wallet to the address of the contract.

Assuming that some time has elapsed, the EV_iAlways to EV_sOr EV_pTwo states develop. A utility cooperative game is written in the form of G ═ P, S, U, where P ═ EV (EV)_s,EV_p) Representing sets of two game groups, S ═ S_s,S_p) Respectively correspond to EV_sAnd EV_pThe set of policies of (a) is,and (3) representing a revenue function set of the participant P under the S strategy pair, wherein each game group has a respective behavior strategy space.

Definition of EV_sHas a policy space of S_s＝(x₁₁,x₁₀,x₀₁,x₀₀) Wherein x is₁₁The electric energy is sold and the electric power information is uploaded; x is the number of₁₀Indicating a willingness to sell electric energy, but a reluctance to upload electric power information; x is the number of₀₁The system is used for indicating that the system is unwilling to sell electric energy but willing to upload electric power information; x is the number of₀₀Indicating that the user is neither willing to sell electric energy nor upload electric power information; EV (electric vehicle)_pHas a policy space of S_p＝(y₁₁,y₁₀,y₀₁,y₀₀) Wherein y is₁₁，y₁₀，y₀₁And y₀₀And S_sSimilarly, as shown in table 2.

TABLE 2S of the invention_sAnd S_pStrategy space of

(3) Contract execution is instigated.

1) After the intelligent contract reaches the triggering condition, the intelligent contract is pushed to an execution queue, and the system automatically executes the intelligent contract in sequence according to the arrangement sequence. LAGs obtaining current market power price T_priceAnd publishing the electric automobile in the transmission range. At game group EV_sIn (1), selecting strategy x_ijHas a probability of p_ijAnd p is_ij∈[0,1]. At game group EV_pIn (1), selecting policy y_ijHas a probability of q_ijAnd q is_ij∈[0,1]. We select EV's separately_sAnd EV_pOne strategy is to calculate the revenue function separately, and the like.

Game-playing group EV_sSelection policy x_ijProbability of return (3)

Wherein λ₁Is EV_sThe number of nodes participating in the game in the group is epsilon, and epsilon is the connection probability value of the two vehicles within the time T.

Game-playing group EV_pSelection policy y_ijProbability of return (3)

Similar λ₂Is EV_pThe number of nodes participating in the game in the group.

TABLE 3 parameter notation and description

Node revenue probabilityAnd equation (9) into the following equations, respectively, EV can be calculated_sAnd EV_pFinal revenue under four strategiesThe symbols of the parameters used in the model are shown in table 3.

2) The participator completes the electric power transaction and fund settlement, and arranges and packs the data generated by the transaction. And the contract reads the energy consumption value of the intelligent instrument arranged in the electric automobile so as to verify the generated and consumed electric quantity and authorize the payment of the energy currency.

3) The intelligent contract system built in the bottom layer of the energy source block chain automatically completes the processing process of the contract, and has non-tamper property and open transparency. Further, the system updates the energy block chain after the contract is executedState of (1), EV_iThe wallet data records and account balances are also updated.

Example 4. The security analysis of the system of the invention.

The invention uses asymmetric encryption and signature verification techniques to ensure safe access and data reliability during power transactions and can resist many traditional security attacks. The signature messages are stored on a chain of energy-sourcing blocks, which means distributed storage of data, and should also meet the following security requirements:

(1) and (3) privacy protection of the nodes: in the present invention, each EV_iRandom use of dynamic pseudonym identity PID_ij. The attacker is not aware of the random number r_ijIn the case of (3), it is not possible to derive an EV from a one-time pseudonym_iThe identity of (c). Therefore, the attacker cannot easily find the real identities of the vehicle and the user, and cannot brute force the encrypted data in a short time.

(2) Non-forgeability: first, the vehicle service center or charging infrastructure authenticates the current vehicle. The legal electric vehicle passing the identity authentication can only carry out the electric power transaction, otherwise, the electric vehicle is regarded as an invalid vehicle. The distributed nature of the energy sourcing blockchain is combined with digital signature transactions so that an attacker cannot forge a message. And, user information and EV_iThe license plate numbers are bound together in the registration phase and are placed in a trusted authority as unique identifiers.

(3) Tamper resistance: unlike traditional centralized data storage, the energy block chain is a distributed storage structure. All participants in the network maintain a distributed ledger together, with each participant maintaining a copy. The block chain encrypts data by using an asymmetric cryptography principle and forms strong calculation power by using a PBFT consensus algorithm.

(4) Security verification of data storage: the invention uses PBFT consensus mechanism to carry out public audit and verification on encrypted transaction data, thereby ensuring the authenticity of the data. Even if f is less than or equal to (n-1)/3 nodes in the system are attacked or damaged, the system can normally complete the verification work of the data.

(5) Resisting man-in-the-middle attack: to accomplish the interception, the man-in-the-middle maintains a communication connection with both the buyer and the seller of the electric vehicle at the same time, and both believe that it is difficult to communicate with each other in a secure connection. In EV_iGenerating a random number r during a power transaction with a charging infrastructure or LAG_ijAnd dynamic encrypted PID_ijEach link is guaranteed. R of attacker and buyer and seller_ijAnd PID_ijUnlike, communication with the user cannot be established through man-in-the-middle attacks.

(6) Resistance to collusion attack: the invention provides a novel game-based incentive contract applied to a power transaction process, and the benefit of a node is improved through an incentive mechanism of rewarding energy coins. If a legal electric vehicle node wants to collude other electric vehicle nodes to carry out negative transaction or illegal attack, the reward of the energy currency is reduced, so that funds for carrying out electric power transaction cannot be provided, and other nodes are forced to abandon the collusion attack.

Example 5. And (5) evaluating and comparing the performances of the system.

(1) Performance overhead comparison: in the power transaction, the performance overhead mainly includes communication overhead of sending messages and verification overhead after receiving the messages. The communication overhead typically includes vehicle identity information, certificates, timestamps, pseudonyms, etc., assuming that the original message size is not considered. The communication overhead of sending a message by SPRING includes 189 bytes, the communication overhead of IBCPA includes 833 bytes, and the communication overhead of EAAP includes 220 bytes. However, the scheme of the present invention requires only 67 bytes. As shown in table 4, the comparison of the communication overhead and the verification overhead of the present invention with the other three schemes is summarized. Where n denotes the receipt or verification of n messages, T_parRepresenting the time of the bilinear pairing operation, T_mulRepresents the time of a dot product operation on an elliptic curve, and T_mtpIndicating the time of the Map-To-Point hash operation.

It can be seen from the comparison analysis that the communication overhead generated by sending the same number of messages is only 35.45% of the SPRING scheme, 8.04% of the IBCPPA scheme, and 30.45% of the EAAP scheme. Therefore, the scheme of the invention can save 64.55% of communication overhead at the lowest.

The invention adopts an experimental method represented by an MNT curve with an embedding degree of 6 and an index of 160 bits. Performed on an Intel Pentium IV 3.0-GHz machine in the experimental environment, the following results were obtained: t is_par＝4.5ms，T_mtp＝0.6ms，T_mul＝0.6ms。

TABLE 4 comparison of performance overheads for different schemes

The verification delay time between different schemes is compared when verifying n signatures. Will T_par，T_mtp，T_mulThe values of (a) are substituted into table 4, and the delay time of each scheme in verifying the signature is calculated separately. When the delay time of the time SPRING scheme for verifying a single signature is 20.1ms, the delay time of the IBCPPA scheme is 15.9ms, and the delay time of the EAAP scheme is 12 ms. However, the scheme of the present invention only needs 11.4ms to verify a signature, accounting for only 56.72% of the SPRING scheme, 71.70% of the IBCPPA scheme and 95% of the EAAP scheme. The advantage of the scheme of the present invention in verification delay time becomes more and more apparent as the number of signatures increases.

(2) Contract performance evaluation is motivated.

In the incentive contract scenario of the present invention, the execution is strictly performed according to the conditions specified by the contract, and a policy for maximizing the profit of each group needs to be selected. In order to effectively evaluate the new model provided by the invention, MATLAB simulation software is used as a platform to establish a simulation environment for testing the performance of the scheme of the invention in the aspect of incentive income.

Due to group EV_sAnd group EV_pP in the policy space of₁₁+p₁₀+p₀₁+p₀₀Assuming that the probability of selecting each strategy is the same, i.e. p_ij＝q_ij0.25. Assuming that the number of the vehicles participating in the game on average is 2, the parameter θ in the poisson distribution is 2, and because the probability that two vehicles are connected is relatively large under normal conditions, i.e., epsilon is set to 0.8. According to vehicle incomeAgreement of reward and consumption energy currency, and setting income parameter e_sell＝6，e_receive＝4，e_r-uploadSetting energy consumption parameter e at the same time as 5_buy＝6，e_cha-discha＝3，e_c-upload2. All the set parameters are calculated by substituting them into equations (12) and (13), and plotted as shown in fig. 7.

The invention respectively calculates EV_sSelection policy x₁₁Revenue function ofAnd EV_pSelection policy y₁₁Gain function ofThe revenue functions of the other strategies, as shown in equations (14) and (15), and so on. As can be seen from FIG. 7, EV_sIf policy x is selected₀₀It obtains the least revenue, selects strategy x₁₁It obtains the greatest revenue, selects strategy x₁₀Ratio selection strategy x₀₁The gain of (2) is a little larger. Thus, the vehicle would like to obtain more revenue and would need more contribution power and upload information, consistent with the incentive settings of the present invention. And as the number of game vehicles increases, the income can be stabilized at a fixed value.

As shown in FIG. 8, EV is responsible for the initial period_pPurchase of Power, selection of policy y₁₁And y₁₀The energy bank note is paid out. But with the increase of the game vehicles, the profit is finally generated, and the strategy sequence of selecting the profit from small to large is y₀₁＞y₁₁＞y₀₀＞y₁₀Also consistent with the excitation settings of the present invention. The same gain will eventually settle at a fixed value.

Vehicle participating in gameGroup EV_sAnd EV_pFor policy set x_ijOr y_ijTo optimize the countermeasureOrSatisfies the following conditions:

equations (16) and (17) above satisfy the game population EV, respectively_sAnd EV_pNash equilibrium of (1). As can be seen from the definition of nash equilibrium, each participant in nash equilibrium cannot obtain higher benefit by breaking away from the strategy in nash equilibrium strategy set, and the strategy of each participant in nash equilibrium strategy set is the optimal strategy for other participating vehicle strategies.

The two group game simulation experiment results show that the excitation contract model can effectively excite nodes to cooperate, so that collusion attack is avoided.

Claims

1. A safe electric power transaction and excitation system of an electric automobile based on an energy source block chain is characterized by comprising the electric automobile, a charging infrastructure, a vehicle service center, a smart grid and a local aggregator unit, wherein bidirectional information interaction is adopted among the units, and the units simultaneously establish information interaction with an energy source block chain distributed account book to complete safe and credible transaction of the electric automobile and the charging infrastructure; the charging infrastructure comprises a large-scale charging station, a private charging pile and a battery replacement station;

the information interaction and safe and credible transaction comprises the following steps:

(S01): respectively aligning electric vehicles EV in vehicle service center_iPrivate charging pile CP_jAnd large-scale charging station CS_kAnd a battery exchange station BES_nThese nodes register to obtain the real identity RID needed by transaction authentication_mAnd basic information of a private key s;

(S02): charging infrastructure collects and aggregates power prices T of transactions_priceTime of transaction T_timeAnd address T of the transaction_locationInformation, denoted T_n＝{T_price,T_time,...,T_location}; carrying out digital signature and verifying the authenticity of the identity of the electric automobile and the reliability of the message by adopting an elliptic curve based bilinear pairing algorithm; if the identity of the vehicle is suspicious or illegal, the communication is terminated and the information of the illegal vehicle is recorded; if the identity of the vehicle passes and is legal, continuing to prepare for receiving the transaction information uploaded by the vehicle;

(S03): the signed electric power transaction information SM_ijCaching the data in a recording pool of a data processor until the size of the data in the recording pool is equal to the size of a data block, broadcasting the data block to a consensus node of the whole network after waiting for random time, and using a Byzantine fault-tolerant consensus mechanism to achieve an agreement;

(S04): the charging infrastructure acquires the right to record the data block, adds the right to the tail end of the energy block chain to increase the height of the whole chain by one, and simultaneously broadcasts the data to other nodes of the whole network to synchronously store the data of the block chain; on the other hand, the system awards a corresponding number of "energy coins" to the charging infrastructure;

2. The electric vehicle secure power transaction and excitation system based on energy source block chain as claimed in claim 1, wherein the step (S01) of registering the electric vehicle and the charging infrastructure, comprises the following steps:

to what is neededSome electric vehicles are numbered EV_i＝(EV₁,EV₂,...,EV_μ) 1,2,. eta., i; private charging pile number is CP_j＝(CP₁,CP₂,...,CP_μ) μ ═ 1,2,. ·, j; the serial number of the large-scale charging station is CS_k＝(CS₁,CS₂,...,CS_μ) μ ═ 1,2,. ·, k; battery replacement station number BES_n＝(BES₁,BES₂,...,BES_μ)，μ＝1,2,...,n；

1) All nodes register with the vehicle service center, and obtain initialized system parameters and authentication information: the charging infrastructure acquires public parameters for verifying the identity of the electric automobile, wherein the public parameters comprise an identity ID, a license plate number, a public key and a private key;

3. The system for electric vehicle secure electric power transaction and excitation based on energy source block chain as claimed in claim 1, wherein the digital signature and verification in step (S02) comprises the following steps:

1) firstly, an elliptic curve E meeting the theoretical requirement of an elliptic curve cryptosystem is selected_pAfter (a, b), randomly selecting a prime number q, andwhereinIs a finite field; two cyclic groups are respectively G₁And G₂And their order is q, wherein G₁Expressed as a cyclic addition group, G₂Is a cyclic multiplicative group;

2) the vehicle service center randomly selects two prime numbers P and s, wherein s is a private key of the vehicle service center,and isWith 1 < s < q, P is the cycle group G₁One of the generators, and finds the public key P_pub；

3) According to the real identity RID_iCalculate pseudonym PID_iAnd the private key SK of the jth message_ijAnd an authentication parameter a_ijAnd b_ij(ii) a Finally generating a pair message M_ijSigned message SM_ijThe charging infrastructure verifies the message signature, which can be divided into single message verification and batch verification.

4. The electric vehicle safety electric power transaction and excitation system based on the energy source block chain as claimed in claim 1, wherein the step (S05) is as follows:

1) generation of an incentive contract: the electric vehicle is registered in a vehicle service center or a government agency to obtain authentication parameters including EV_iPublic and private key pair (P)_pub,SK_i) And address W of account_i(ii) a All authentication information uniquely identifies the identity by binding license plate numbers and customer information;

wherein SM_iIs defined as a message M_iThe digital signature of the hash digest of (1); by contract rules and terms, local aggregator and EV_iAn agreement is reached, and respective private keys are used for signature; packing the deployed contracts into Docker mirror images, and carrying out contract inspection on Docker sandboxes;

2) issuing of incentive contracts: the cooperative game is written in a form of G ═ P, S, U, where P ═ EV (_s,EV_p) Representing sets of two game groups, S ═ S_s,S_p) Respectively correspond to EV_sAnd EV_pThe set of policies of (a) is,representing a revenue function set of the participant P under the S strategy pair, wherein each game group has a respective behavior strategy space; definition ofEV_sHas a policy space of S_s＝(x₁₁,x₁₀,x₀₁,x₀₀) Wherein x is₁₁The electric energy is sold and the electric power information is uploaded; x is the number of₁₀Indicating a willingness to sell electric energy, but a reluctance to upload electric power information; x is the number of₀₁The system is used for indicating that the system is unwilling to sell electric energy but willing to upload electric power information; x is the number of₀₀Indicating that the user is neither willing to sell electric energy nor upload electric power information; EV (electric vehicle)_pHas a policy space of S_p＝(y₁₁,y₁₀,y₀₁,y₀₀) Wherein y is₁₁，y₁₀，y₀₁And y₀₀And S_sSimilarly;

all participating local aggregators and EVs_iSufficient deposit should be paid from the respective wallet to the address of the contract;